Brake master cylinder capable of monitoring position and movement of brake pedal

The invention relates to a brake master cylinder capable of monitoring the position and movement of a brake pedal, belonging to the field of automobile brake production. A first piston and a second piston are in sleeve joint with the inside of a master cylinder body respectively; a brake lamp sensor is fixedly connected with the master cylinder body; the distance between the center of the brake lamp sensor and the flange end surface of the master cylinder body is S1; a step thin wall is arranged at the front end of the first piston; a piston flaring is arranged at the edge of the step thin wall; a magnet is fixedly connected with the first piston through the piston flaring; the distance between the center of the brake lamp sensor and the center of the magnet is S2; and a check ring is fixedly connected with the two ends of the magnet respectively. With a novel structure, the brake master cylinder provided by the invention can effectively monitor the position and movement of an automobile brake pedal so that a driver can better master the brake status. The brake master cylinder provided by the invention is a master cylinder integrating a device for detecting the position of a piston in the cylinder body, and is particularly suitable for a motor vehicle control system with a running power adjustment device.